Method of manufacturing a needled heat-shrinkable tufted pile fabric

ABSTRACT

A process for the manufacture of tufted pile fabric in which the pile yarns are tufted on a backing comprising primarily needled heat-shrinkable synthetic thermoplastic fibers with the fibers of at least one surface bonded together, fibers in the interior of the backing remaining unbonded, and the fabric after tufting is subjected to a widthwise heat shrinkage treatment with the dimensions of the fabric controlled both widthwise and lengthwise of the fabric, and at a controlled temperature.

United States Patent David B. Parlin Thompsonvllle, Conn.;

Ronald V. Canova, East Longmeadow, Mass.

Aug. 14, 1969 Sept. 21, 1971 Bigelow-Sanford Inc.

Thompsonville, Conn.

[72] Inventors [21 Appl. No. [22] Filed [45] Patented [73 Assignee [54]METHOD OF MAN UF ACTURING A NEEDLED HEAT-SHRINKABLE TUFTED PILE FABRIC3,075,865 1/1963 Cochran 156/148 X 3,309,252 3/1967 Adler 156/723,360,421 12/1967 Sands 156/148 3,366,529 1/1968 Olson 161/67 3,383,2595/1968 C0chran.... 156/148 3,394,043 7/1968 Parlin et al. 161/673,451,109 6/1969 Klein 28/722 3,476,636 11/1969 Crosby 161/67 3,506,5294/1970 Sanders..... 161/67 3,515,622 6/1970 Jordan 156/72 X PrimaryExaminer-Benjamin R. Padgett Assistant Examiner-Gary G. SolystA!t0rneyE. T. LeGates ABSTRACT: A process for the manufacture of tuftedpile fabric in which the pile yarns are tufted on a backing comprisingprimarily needled heat-shrinkable synthetic thermoplastic fibers withthe fibers of at least one surface bonded together, fibers in theinterior of the backing remaining unbonded, and the fabric after tuftingis subjected to a widthwise heat shrinkage treatment with the dimensionsof the fabric controlled both widthwise and lengthwise of the fabric,and at a controlled temperature,

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METHOD OF MANUFACTURING A NEEDLED HEAT- SHRINKABLE TUFTED PILE FABRICThe present invention relates to the manufacture of tufted pile fabricand more particularly to the manufacture of tufted pile fabric whereinthe fabric backing is a nonwoven fibrous fabric containing a predominantproportion of heat-shrinkable synthetic thermoplastic textile fibers.

An object of the invention is to provide a method of making a tuftedpile fabric having a backing predominantly composed of nonwovenheat-shrinkable synthetic thermoplastic fibers in which the fabric maybe tufted at a wider width than the desired final width of the fabric,whereby large pile yarns may be used and the tufting apparatus may beone containing relatively larger needles or one having the needles setat a wider gauge, or both.

Another object of the invention is to provide a method for themanufacture of tufted pile fabric having such a backing which willproduce cut pile fabrics wherein any objectionable rowiness" of the pileface is reduced or eliminated.

Another object is to provide a tufted pile fabric having such a backingstructure in which any tendency of the completed fabric to shrinkwidthwise when exposed to unduly high temperatures is reduced.

A further object is to provide such a process wherein a single tuftingmachine may be used for the manufacture of tufted pile fabrics of twodifferent widthwise gauges with the same single set of high-low patterncontrol attachments.

Other objects, features and advantages of the invention will becomeapparent from the following description of an illustrative embodiment ofthe invention wherein reference is made to the accompanying drawing, inwhich FIG. 1 is a plan view, somewhat schematic, illustrating theprocess and showing apparatus on which the process may be practiced;

FIG. 2 is a vertical sectional view taken on line 22 of FIG. 1 lookingin the direction of the arrows;

FIG. 3 is a perspective view of a tufted pile fabric having a backing ofthe type made use of in the invention; and,

FIG. 4 is a similar perspective view of the fabric of FIG. 3 after ithas been treated by the process of the invention.

In accordance with the invention we provide a method of making a tuftedpile fabric, such as a pile fabric floor covering, employing a sheetbacking fabric which comprises a needled sheetlike web of intermixedtextile fibers in which the majority of the fibers are of aheat-shrinkable synthetic thermoplastic material, preferablypolypropylene, the web being needled throughout its thickness at amultiplicity of closely spaced points distributed over its surface withfibers at different levels of the web having portions which aredisplaced vertically relative to the thickness of the web at saidpoints, the exposed fibers on at least one exterior surface of the webbeing bonded together, the needled web also including fibers locatedbetween the exterior surfaces thereof which are not bonded together andare mobile relative to each other, the backing fabric having a pluralityof spaced pile yarns extending therethrough at spaced points along eachyarn to provide a plurality of pile elements upstanding in rows from oneface of the backing fabric, the yarns extending from the pile elementsthrough the backing fabric and along its other face to adjacent pileelements, and the portions of said pile yarns passing through thebacking fabric being resiliently gripped by the unbonded fibers of thebacking fabric, thereafter shrinking the backing fabric by continuouslymoving the backing fabric in a direction lengthwise of the pile yarnsthrough a heating zone, preferably a heating zone containing a heatedatmosphere, to heat the shrinkable fibers to a temperature above thetemperature at which they shrink but not to heat them above their fusiontemperature for any appreciable length of time, while substantiallyinhibiting lengthwise shrinkage of the backing fabric by engaging thebacking fabric along a line transverse to said lengthwise directionadjacent one side of said heating zone and feeding it toward theinterior of said heating zone at a controlled rate of advance and againengaging said backing fabric along another line transverse to saidlengthwise direction adjacent to the opposite side of said heating zoneand withdrawing the backing fabric from the interior of said zone at thesame controlled rate, and controlling shrinkage of said backing fabricin the transverse direction by continuously engaging each side edge ofsaid backing fabric and constraining each of said edges to move along afixed line inclined toward the middle of said backing fabric as ittravels in said heating zone. Preferably the side edges of the fabricare engaged and constrained to remain at a constant distance apartduring the final portion of the travel of the fabric within the heatingzone.

Although the invention is not confined thereto, the backing fabricconveniently may be a backing fabric of the character disclosed inParlin et al. U.S. Pat. No. 3,394,043 issued July 23, 1968, thedisclosure of which patent is incorporated herein by reference.Generally speaking, the backing fabric of U.S. Pat. No. 3,394,043 iscomprised principally of fibers of a thermoplastic material, such aspolypropylene or other polyolefins having similar characteristics,including mixtures, which have been subjected to needling and with thefibers on at least one surface of the backing fabric being bondedtogether. The fibers employed may be those termed waste fibers in thetrade. The fabric may be fon'ned by distributing the fibers by means ofgarnets in one or more superimposed layers on a carrier such as alow-count cotton cheesecloth. The cheesecloth with the fibers depositedthereon is then moved to a needling machine where the web is subjectedto a needling operation which causes the fibers to be intimatelyintertwined and interengaged with each other throughout the thickness ofthe web, particularly at the points of needling, and causes fibers fromdifferent levels of the web to be intermixed in more intimate engagementwith each other and imparts strength to the web. A closed barb needle ofsmall diameter, such as a 032 fine-felt triple-barb needle may beemployed for this purpose. Needling preferably is performed with thecheesecloth adjacent to the lower face of the web so that the ends ofsome fibers are forced through the open mesh of the cheesecloth.Thereafter when the surface fibers of this side of the fabric are fusedor bonded together they also engage with and grip the threads of thecheesecloth and thus prevent slippage or movement of the cheeseclothrelative to the web of needled fibers. Under these conditions the fusedfibers and the threads of the cheesecloth combine to resist and overcomethe forces exerted on the backing fabric as a result of tufting andpermit the desired dimensions to be maintained. When the fabric istufted it is preferable that the cheesecloth or the like be adjacent tothe upper or pile face of the fabric.

After needling, fibers on one or both exterior surfaces are bondedtogether to a flattened and hardened condition with the interior fibersremaining unbonded and mobile relative to each other. This may be doneby heating the surface fibers to their melting temperature so as to fusethe surface fibers without fusing the fibers of the interior of the web.Such bonding may be accomplished with fibers of polypropylene having amelting point between 310 and 320 F. by heating the surface fibersbriefly to a temperature between 325 and 350 F. by contact with rollers.When heated in this manner the fibers in the center or interior of theweb do not reach their melting temperature and will remain unbonded orunfused and mobile with respect to each other. Such bonding tends toincrease the tensile strength of the web and reduce its elongation andthe bonded or fused surface can pass beneath the needles of the tuftingmachines during the tufting operation without excessive interference orobjectionable drag.

The backing may be made entirely from polypropylene fibers or frommixtures of polypropylene fibers with fibers of other materials such asnylon, rayon,. acrylic resins, and polyesters, or mixtures thereof. Asatisfactory backing or support fabric for tufted carpets may be madefrom polypropylene fibers of 3 to 15 denier, which are commonly producedcommercially.

An example of a suitable mixture of fibers is a mixture containing 65percent of 6 denier crimped polypropylene fibers of i k-inches staplelength, 25 percent of 3 denier crimped polypropylene fibers of 3-inchesstaple length and percent of rayon fibers of 3-inches staple length.

The unbonded or unfused fibers in the interior of the backing retaintheir resilient characteristics and thus have a tendency to close on theportions of the pile yarns which extend through the backing fabric andto hold the pile yarns in place more effectively in the drawing of theloops than is the case with loosely woven backing fabric such as burlap.

Preferably the bats or mats of fibers issuing from the garnet aredisposed transversely in the web of backing material formed from them,as in U.S. Pat. No. 3,394,043, so that the fibers are disposedpredominantly transversely, i.e. widthwise, of the web. It is generallydesirable to deposit more than one layer of the mat issuing from thegarnet on to the cheesecloth, or other carrier, so as to obtain a moreeven and uniform distribution of the fibers in the backing fabric.

In lieu of cheesecloth, we may employ a layer of longitudinallyextending polyester filaments, threads or yarns, or a layer of anoriented synthetic polymer film, preferably a polypropylene film, whichis fibrillated by the needling operation.

The pile elements are formed on the backing in an entirely conventionalmanner by the use of the usual tufting machines employing a gang ofreciprocating needles, as is well known in the art.

An illustrative process in accordance with the invention will now bedescribed. Referring to the drawing, a tufted pile fabric floor covering2 having pile tufts 3 and a nonwoven backing 4 of the characterheretofore described is supplied from a supply roll 6. The roll 6 isprovided with pins or spikes 7 which prevent slippage of the backing 4on the roll and the roll 6 is driven in any suitable manner at acontrollable speed. The roll 6 thus serves to engage the backing along atransverse line and release the fabric 2 at a controlled rate. Thetufted pile fabric 2 moves forwardly in the direction of the arrow 8over a guide roll 10. The opposite edges of the fabric are engaged by apair of tenter chains l2, 14. The tenter chains l2, l4 carry upstandingpins 16 and at their front ends pass about guide rolls 18, 20respectively so that their inner flights move beneath the edges of thefabric 2, as shown, in position to engage the edges on the pins 16. Tworotary brushes 22, 24 engage the upper or pile face of the fabric 2above the pins as shown and press the edges downwardly to engage theedges of the fabric on the pins 16, as shown to best advantage in FlG.2.

Upon leaving the brushes 22, 24 the fabric 2, with its edges engagedwith the tenter chains 12, 14, enters a heating zone in a heatingchamber 26. The heating chamber 26 contains air heated to theappropriate temperature by steam-circulating coils 28. In the case of atufted fabric having a backing which is composed predominantly ofpolypropylene fibers as in U.S. Pat. No. 3,394,043, the temperature inthe heating chamber 26 is maintained in the range 3 l 5-320 F.

Adjacent the entrance to the heating chamber 26 the inner faces of thetenter chains 12, 14 pass over guide rolls 32, 34 which serve tosuitably space the tenter chains in their extent from the rollers 18, 20to the guide rolls 32, 34. Ordinarily this spacing will be such that thefabric 2 as it is engaged and held by the pins 16 is maintained at itsinitial width. Thereafter the outer faces of the tenter chains 12, 14pass over the guide rolls 36, 38 which are spaced more closely togetherthan the guide rolls 32, 34 so that the tenter chains and the edges ofthe fabric 2 engaged by them are constrained to move along a fixed lineinclined toward the middle of the backing fabric. As the fabric 2 movesinto the heating zone in the heating chamber 26 its temperature israised and as the temperature of the shrinkable fibers in the backingreach their shrinking temperature the fabric shrinks. As the fabricshrinks, the inclined portions of the tenter chains between guide rolls32, 34 and guide rolls 36, 38 control the shrinkage so that it isuniform and of the desired amount.

As the tenter chains leave the guide roll pair 36, 38 they pass to theguide rolls 40, 42 engaging their outer surfaces and about which theypass so that their return flights 44, 46 are passed about the guiderolls 48, 50 and 52, 54 to return to the guide rolls 18, 20,respectively. The guide rolls of the pair 40, 42 are spaced apart thesame distance as the guide rolls 36, 38 so that the side edges of thefabric 2 are maintained a constant distance apart, corresponding to theshrunken width of the fabric, during the final portion of the travel ofthe fabric within the heating zone.

Adjacent the exit side of the heating zone the fabric 2 is engaged alonganother transverse line by a spike roll 56 which is driven in anysuitable manner at the same rate as the roll 6 to withdraw the fabric 2from the heating zone at the same speed as it is released from the roll6 so as substantially to inhibit lengthwise shrinkage of the backingfabric. When the shrinkable fibers in the backing 2 are disposedpredominantly in the transverse direction, this disposition of thefibers aids in confining the shrinkage of the fabric to a widthwiseshrinkage. Also, when the backing contains longitudinally extendingpolyester strands, which do not shrink at the temperatures which aresufficient to adequately shrink the backing made predominently ofpolypropylene fibers, this arrangement also aids in confining shrinkageto the widthwise direction.

The fabric 2 issuing from the heating chamber 26 is lifted from the pins16 of the tenter chains at 58 and is finally wound up on any suitabletakeup arrangement such as the takeup roll 60.

FIG. 3 illustrates the tufted pile fabric 2 in the condition in which itenters the apparatus of FIGS. 1 and 2. The pile yarns form the pileelement 3 upstanding from one face of the backing 4 with the yarnextending from the pile elements through the backing 4 and along thelower face of the backing at 62 to connect with adjoining pile elements.ln this embodiment the backing does not contain a cheesecloth layer butinstead contains a layer of polyester threads or yarns 64, bonded to thesuperficial polypropylene fibers at the front or upper face of thetufted fabric. Such arrangement aids in confining shrinkage to thetransverse direction, which is crosswise of the strands 64.

The tufted pile fabric in the condition in which it issues from theapparatus of FIGS. 1 and 2 is shown in FIG. 4. Here the backing isnarrower than in FIG. 3. We have found that a tufted pile fabric floorcovering may very conveniently be reduced in width by 20 percent, thatis reduced from a standard 15-foot width to a width of 12 feet, when thebacking is composed of polypropylene fibers, if the temperature in theheating chamber 26 is maintained in the ranges 3 l5320 F the length ofthe chamber is approximately 21 feet, the distance between the roll pair32, 34 and the roll pair 36, 38 is approximately 13 feet, and thedistance from the roll pair 36, 38 to the exit end of the chamber isapproximately 8 feet, and the speed of the fabric through the heatingchamber 26 is approximately 4% feet per minute. Thus a fabric tufted ona 5/32-inches gauge machine finishes to a ;b-int2hes gauge-type fabricor a /s-inches gauge fabric finishes to a 1/ 10-inch gauge fabric, andso on. In this case, the roll pairs 32, 34 and 36, 38 are adjusted sothat the spacing between the tenter chains 12, 14 decreases by 20percent in passing from one roll pair to the other.

We have found that when applied to cut pile tufted fabrics, our processprovides a completed fabric in which the objectionable rowiness oftenassociated with cut pile in tufted carpet is greatly reduced or entirelyeliminated. We think this may be due to the legs of the cut tuftsturning as the fabric shrinks and compresses adjacent cut legs againstone another so that the objectionable visual effect due to some of thetufts being J-tufts, and others not, is greatly reduced. in any case,whatever the explanation may be, we have found that cut pile I tuftedfabrics, even those having a pronounced degree of rowiness," have thisdefect either materially reduced or entirely eliminated when treated bythe process of the invention.

We claim:

1. The method of making a tufted pile fabric which comprises providing asheet backing fabric comprising a needled sheetlike web of intermixedtextile fibers in which the majority of said fibers are of aheat-shrinkable synthetic thermoplastic material, said web being needledthroughout its thickness at a multiplicity of closely spaced pointsdistributed over its surface with fibers at different levels of the webhaving portions which are displaced vertically relative to the thicknessof the web at said points, the exposed fibers on at least one exteriorsurface of said web being bonded together, said needled web alsoincluding fibers located between the exterior surfaces thereof whichfibers are not bonded together and are mobile relative to each other,said backing fabric having a plurality of spaced pile yams extendingtherethrough at spaced points along each yarn to provide a plurality ofpile elements upstanding in rows from one face of the backing fabric,said yarns extending from the pile elements through the backing fabricand along its other face to adjacent pile elements, the portions of saidpile yarns passing through the backing fabric being resiliently grippedby the unbonded fibers of the backing fabric, thereafter shrinking saidbacking fabric by continuously moving said backing fabric in a directionlengthwise of said pile yarns through a heating zone to heat saidshrinkable fibers to a temperature above the temperature at which theyshrink but not above their fusion temperature for any appreciable lengthof time, while substantially inhibiting lengthwise shrinkage of saidbacking fabric by engaging said fabric along a line transverse to saidlengthwise direction adjacent one side of said heating zone and feedingit toward the interior of said heating zone at a controlled rate ofadvance and again engaging said backing fabric along another linetransverse to said lengthwise direction adjacent the opposite side ofsaid heating zone and withdrawing the backing fabric from the interiorof said zone at the same controlled rate, and controlling the shrinkageof said backing fabric in the transverse direction by continuouslyengaging each side edge of said backing fabric and constraining each ofsaid edges to move along a fixed line inclined toward the middle of saidbacking fabric as it travels in said heating zone.

2. The method of claim 1 wherein a major proportion of saidthermoplastic fibers are polypropylene fibers and the temperature ofsaid heating zone is maintained within the range 3 l 5-3 20 F.

3. The method of claim 1 wherein said backing fabric includeslongitudinally extending polyester yarns bonded to the surface fiberswhich are bonded together.

4. The method of claim 1 wherein the side edges of said fabric areengaged and constrained to remain at a constant distance apart duringthe final portion of their travel within the heating zone.

5. The method of claim 1 wherein said heating zone contains a heatedatmosphere.

6. The method of claim 1 wherein said fibers are disposed predominantlytransversely of said backing fabric.

7. The method of claim 1 wherein the exposed fibers located at the otherexterior surface of said web are bonded together.

8. The method of claim 2 wherein said backing fabric includeslongitudinally extending polyester yarns bonded to the surface fiberswhich are bonded together.

9. The method of claim 8 wherein the side edges of said fabric areengaged and constrained to remain at a constant distance apart duringthe final portion of their travel within the heating zone.

10. The method of claim 9 wherein said heating zone contains a heatedatmosphere.

1 1. The method of claim 10 wherein said fibers are disposedpredominantly transversely of said backing fabric and wherein theexposed fibers located at the other exterior surface of said web arebonded together.

12. The method of claim 2 wherein the side edges of said fabric areengaged and constrained to remain at a constant distance apart duringthe final portion of their travel within the heating zone.

13. The method of claim 12 wherein said heating zone contains a heatedatmosphere.

14. The method of claim 2 wherein said heating zone contains a heatedatmosphere.

15. The method of claim 4 wherein said heating zone contains a heatedatmosphere.

16. The method of claim 8 wherein said heating zone contains a heatedatmosphere.

2. The method of claim 1 wherein a major proportion of saidthermoplastic fibers are polypropylene fibers and the temperature ofsaid heating zone is maintained within the range 315* -320* F.
 3. Themethod of claim 1 wherein said backing fabric includes longitudinallyextending polyester yarns bonded to the surface fibers which are bondedtogether.
 4. The method of claim 1 wherein the side edges of said fabricare engaged and constrained to remain at a constant distance apartduring the final portion of their travel within the heating zone.
 5. Themethod of claim 1 wherein said heating zone contains a heatedatmosphere.
 6. The method of claim 1 wherein said fibers are disposedpredominantly transversely of said backing fabric.
 7. The method ofclaim 1 wherein the exposed fibers located at the other exterior surfaceof said web are bonded together.
 8. The method of claim 2 wherein saidbacking fabric includes longitudinally extending polyester yarns bondedto the surface fibers which are bonded together.
 9. The method of claim8 wherein the side edges of said fabric are engaged and constrained toremain at a constant distance apart during the final portion of theirtravel within the heating zone.
 10. The method of claim 9 wherein saidheating zone contains a heated atmosphere.
 11. The method of claim 10wherein said fibers are disposed predominantly transversely of saidbacking fabric and wherein the exposed fibers located at the otherexterior surface of said web are bonded together.
 12. The method ofclaim 2 wherein the side edges of said fabric are engaged andconstrained to remain at a constant distance apart during the finalportion of their travel within the heating zone.
 13. The method of claim12 wherein said heating zone contains a heated atmosphere.
 14. Themethod of claim 2 wherein said heating zone contains a heatedatmosphere.
 15. The method of claim 4 wherein said heating zone containsa heated atmosphere.
 16. The method of claim 8 wherein said heating zonecontains a heated atmosphere.